In regard to Windows platforms. Yes, I used to run the QB64 SDL version on my XP and I would suspect the latest version of QB64 would still run on XP. Now n regard to Win 98; somewhere in the production of the SDL version, Galleon stopped support for Windows 98. It had something to do with some sort of difficulty he was running into where he would have had to duplicate certain new additions to QB64 to work on 98 and XP. I recall I used to run some of the earliest versions of QB64 SDL on my Win 98 but after the version update I had to switch and start using my new XP.
I recall when Mircosoft was just getting started, and they were looking for ideas to name their OS. Back then, they were thinking along the lines of names that would indicate a stable platform that would deliver accurate response in any and all situations. They were entertaining names like "Microsoft Level" and "Microsoft Plum." In keeping with that theme, I submitted my entry of Microsoft Flush... but to this day, I've never heard back. Oh well.
Pete